Egg-type Pullets Research Articles

Effect of constant photoperiods on the laying performance of broiler breeders allowed conventional or accelerated growth

An experiment was conducted at the University of KwaZulu–Natal to assess the effect of constant photoperiods on sexual maturity and egg-laying performance in broiler breeders given two levels of control-feeding during the rearing phase. Cobb broiler breeder females were grown to reach 2·1 kg body weight at 17 or 21 weeks, and maintained on 10, 11, 12, 13, 14 or 16-h photoperiods from 2 days to 68 weeks of age. There were no significant interactions between photoperiod and growth rate for any production parameter. The time required reaching 2·1 kg increased proportionally with photoperiod but, because of delayed sexual development, birds on longer photoperiods consumed more feed to, and were heavier at, sexual maturity than shorter daylengths. The longer-photoperiod birds also had inferior rates of lay in the first half of the cycle, but superior in the second, which, together with the photoperiodic effects on maturity, resulted in birds on 11, 13 or 14 h producing most eggs to 68 weeks, and those on 16 h fewest. It is possible that the pattern of egg production was due to some of the birds on [ges ]13-h photoperiods becoming photorefractory, having a mid-cycle pause, and then spontaneously resuming egg production in the latter half of the cycle. However, a hinge-analysis of current and other data to the more usual depletion age of 60 weeks showed that the combined effects of photoperiod on sexual maturity and egg production resulted in constant 10-h birds producing the highest number of eggs, with numbers decreasing by 3·6 eggs/h of photoperiod above the hinge and 7·8 eggs/h of photoperiod below it. Mean egg weight increased by 0·4 g/h of photoperiod, but the proportion of abnormally large and floor eggs and the incidence of mortality were unaffected by daylength. For each photoperiod, accelerated growth resulted in body weights being heavier than controls at sexual maturity, despite the mean age at maturity being 10 days earlier for the faster-growing birds. Body weights for the two growth groups were not significantly different at 68 weeks. Faster-growth birds consumed 1 kg less feed to 2·1 kg body weight, but 1·3 kg more feed to sexual maturity and 2·7 kg more to 68 weeks, and produced 6 more eggs than, but had similar patterns of egg production to, the conventionally managed controls. Mean egg weight, the proportion of floor eggs and the incidence of mortality were similar for both groups. Notwithstanding that the overall production of abnormally large eggs was low (1·1 eggs per bird); the faster-growing birds produced significantly more than the controls. Egg weight was positively influenced by age at sexual maturity, body weight at sexual maturity and photoperiod, but was unaffected by rate of growth to 2·1 kg per se.These findings show that there are differences between broiler breeders and egg-type pullets in their response to constant photoperiods. It is likely that the factors responsible for these differences, particularly in terms of sexual development, are the exhibition of photorefractoriness by, and the retardational effects of controlled feeding on, broiler breeders.

Dietary protein and energy effects on reproductive characteristics of commercial egg-type pullets reared in arid hot climate

A feeding trial with 10-week-old egg-type commercial pullets was carried out. Nine diets (3 × 3 factorial) were tested, with three protein levels (13, 15 and 17%) and three energy levels (10, 11 and 12 MJ kg −1). From the results it appears that a diet containing 15% protein and supplying 10 MJ kg −1 energy is best for optimal growth and for minimization of the number of days required to reach the point of lay, and the age at 25% and 50% egg production.

Feed Consumption of Egg Strain Pullets at Onset of Lay

An experiment was conducted to investigate the performance of four strains of commercial egg type pullets (A, B, C, and D) from 19 to 30 wk of age. The feed consumption differences during this period as well as feed consumption patterns 10 days prior to and after the first oviposition were of special interest. Two hundred and sixty-four birds (66 birds per strain) were fed a diet formulated to contain 2,750 kcal/kg ME, 17% CP, and 3.4% calcium.Results show that the average age to the first egg and percentage of hen-day egg production were not significantly different among the four strains of birds. However, egg weights of Strain A and C birds were significantly heavier than those of the Strain B and D birds. The birds from Strains B and D had significantly lower body weight than Strain A birds at the end of 18 wk, but body weights were not significantly different at the end of 30 wk.Feed intake per bird per day of pullets from Strains A and C was generally higher than that of those from Strains B and D in the first and second 4-wk period. Some of the consumption differences were significant. Feed intake in the third period (27 to 30 wk) was similar for the four strains of birds. Although different strains showed different feed consumption patterns around the first oviposition, all strains showed a drop on the day of the first oviposition. When the strains were combined, feed consumption was lower on that day than during the 8 days prior to the first oviposition.

Weight Gain of Summer-Reared Egg-Type Pullets Fed Pellets Versus Mash

In an attempt to increase weight gain of egg-type pullets reared under high summer temperatures, pullets were fed feed in either pellet or mash form. Under high temperature rearing conditions, pelleting the diet did not significantly increase 12 to 20-wk body weight gain when compared to effects of the diet fed in mash form. Under a moderate temperature regimen (21 C), pelleting the diet did significantly increase 12 to 20-wk body weight gain in contrast to the effects of the diet fed in mash form.

Research Note: Effect of Beak Trimming on Body Weight and Feed Intake of Egg-Type Pullets Fed Pellets or Mash

Pelleted and mash feed were provided in each of two trials. In the first trial, it was noted that the pullets did not eat the feed that was offered in pellet form. Type of beak trimming appeared to be involved in lowering feed intake. The second trial demonstrated that pullets with either the top beak or both beaks trimmed (block cut) approximately 2 mm from the nostril when offered pellets or mash did not eat feed in pellet form as readily as that in mash form.

Effect of a High Fat Diet Fed Prior to or at Sexual Maturity on Egg Weight ,

This study compared the effects of a low fat, high carbohydrate diet with a high fat diet fed prior to or at the onset of egg production on initial egg weight. Commercial egg-type pullets were assigned to one of three dietary regimens: 1) the control (CON), a low fat, high carbohydrate diet, 2) a high fat (HF) diet containing eight parts of fat, and 3) the high carbohydrate diet provided prelay and the high fat diet during the production period (CHO-HF). The carbohydrate prelay and laying diets contained .990 and .943% fat and had a calculated metabolizable energy (ME) value of 2,831 and 2,697 kcal/kg, respectively. The high fat prelay and laying diets contained 8.959 and 8.484% fat with a calculated ME value of 3,202 and 3,032 kcal/kg, respectively. The first 60 eggs produced by each pullet were collected and weighed.At Egg 60, no significant differences were seen in body weight and abdominal adipose tissue. The CON treatment had a significantly greater liver weight, liver lipid content, and ovary weight than the HF or CHO-HF treatments. The CON and HF treatments had a similar hen-day egg production (HDP). The CHO-HF treatment was slow to adjust to the high fat diet and that may have caused the lower HDP that was seen for this treatment. No indication of a failure to adjust to the high fat diet was noted for the HF treatment. Additionally, a high fat diet resulted in higher egg weights.This study indicates that when fat was supplemented to the diet prior to the onset of egg production, pullets adjusted to the high fat diet and HDP was not adversely affected.

Modified Step-Up Protein Feeding Regimens for Egg-Type Chickens. 2. Protein Level Influence on Growth and Production Performance

Abstract The influence of dietary protein changes on growth from 0 to 20 weeks of age and on egg production from 20 to 72 weeks of age was studied with a commercial strain of White Leghorn chickens. Eight dietary treatments were compared to evaluate two aspects of step-up protein regimens for egg-type pullets: 1) the crude protein (CP) level fed the initial week, and 2) the duration of feeding the 12% CP diet. Treatment 1 served as the control regimen and consisted of feeding 18, 15, and 12% CP diets to 6, 14, and 20 weeks of age, respectively. The percent CP with the respective weeks fed (in parentheses) for Treatments 2 through 8 were as follows: Treatment 2, 18% (0 to 1), 12% (1 to 8), 15% (8 to 14), and 18% (14 to 20); Treatment 3, 18% (0 to 1), 12% (1 to 10), 15% (10 to 16), and 18% (16 to 20); Treatment 4, 18% (0 to 1), 12% (1 to 12), 15% (12 to 16), and 18% (16 to 20); Treatment 5, 16% (0 to 1), 12% (1 t o 10), 15% (10 to 16), and 18% (16 to 20); Treatment 6, 16% (0 to 1), 12% (1 to 12), 15% (12 to 16), and 18% (16 to 20); Treatment 7, 20% (0 to 1), 12% (1 to 10), 15% (10 to 16), and 18% (16 to 20); and Treatment 8, 20% (0 to 1), 12% (1 to 12), 15% (12 to 16), and 18% (16 to 20). All diets were fed ad libitum. At 20 weeks of age, 72 birds from each treatment were housed in laying cages for 52 weeks of egg production. Cumulative feed intake through 20 weeks of age for birds reared on Treatments 2 through 8 was generally less than that of the control birds. Birds reared on Treatments 4 and 8 consumed significantly less protein than the control birds. By 20 weeks of age, average body weights for Treatments 2 through 8 were 4.0, 6.0, 7.6, 4.3, 2.7, 4.6, and 7.6% lighter, respectively, and significantly different from that of the control birds. Dietary treatment did not influence mortality during the growing period. By 28 weeks of age, there were no significant body weight differences among any of the treatments. Age at 50% production, hen-day production, livability, egg weight, percentage egg size, shell deformation, Haugh score, feed per hen-day, and feed per dozen eggs also did not differ significantly among any treatments. Results of this study indicate that feeding a 16 to 20% CP diet for the 1st week of life, followed by a 12% CP diet through 8 to 12 weeks of age, 15% CP to 16 weeks, and 18% CP to 20 weeks of age, produced smaller birds at 20 weeks of age with less total feed intake than the control birds. None of the egg production parameters studied were significantly affected.

Effects of Early Maturation of Brown Egg-Type Pullets, Flock Uniformity, Layer Protein Level, and Cage Design on Egg Production, Egg Size, and Egg Quality

Eight-week-old Harco Sex-Link pullets were assigned to four growing regimens. Feed was restricted to Group 1. The birds reached an average weight of 1.52 kg at 20 weeks of age and were then light stimulated. Group 2 received the same ration ad lib and reached an average weight of 1.64 kg at 16 weeks. At this age they were light stimulated. Birds in Groups 3 and 4 were separated into two weight classes at 8 weeks of age. Those below the median weight received an 18% protein grower ration and those above the median weight a 16% ration. Group 3 birds were grown similarly to Group 1; Group 4 birds were grown similarly to Group 2. At housing, each group was equally divided and given either a 17 or 19% protein layer ration. Two cage designs (standard and reverse) were used and each treatment combination was equally represented. Ad lib-fed, early-housed pullets reached 1.64 kg at 16 weeks of age, but they did not come into production until 19.4 weeks of age. Hen-day percent production (HDP) was significantly less than for the late-housed pullets. Feed per dozen eggs was not affected by the early housing, but early-housed pullets laid significantly smaller eggs and feed per gram egg was significantly increased. Hens in reverse cages on a 19% protein layer ration laid the largest eggs in weight and size. Although early housing had a detrimental effect on average egg weight, it appeared possible to manipulate egg weight and size distribution through a combination of cage design and layer protein.Birds grouped by body weight at 8 weeks had higher uniformity, but this trait was not correlated with egg numbers or size. Moreover, housing body weights were not significantly correlated with egg size, suggesting factors other than body weight were responsible for the smaller eggs from early-housed pullets.

Noted Difference in the Digestive System in Caged and Floor-Reared Commercial Egg-Type Pullets

Two trials were conducted with Single Comb White Leghorn pullets reared from 0 to 19 weeks of age in cages and on litter at the same environmental temperature. Samples were obtained to determine if digestive system differences existed. Criteria measured were gizzard weight and intestine length. Results showed that floor-reared pullets had heavier gizzards with longer intestines than cage-reared pullets. The difference may be caused by consumption of litter by the floor-reared birds.

Effect of Step-Down and Step-Up Protein-Energy Feeding Systems on Egg-Type Pullet Growth and Laying Performance

Four egg-type pullet feeding systems were compared for the production of egg-type pullets. The dietary regimens consisted of either a step-down protein, high energy feeding program; a step-down protein, low energy program; a step-up protein, high energy program; or a step-up protein, low energy program. At 150 days of age all pullets were housed 2 birds per 25.4 × 45.7 cm laying cage and fed a standard layer diet (16% protein). The experiment utilized 2880 birds grown on the floor in a conventional growing house.At 140 days of age, birds subjected to the step-up protein feeding programs were 82 g smaller in mean body weight, had higher mortality, and consumed less feed than the birds on the step-down protein feeding programs. Body weights at 140 days of age were 1.17 and 1.09 kg for the step-down and step-up feeding programs, respectively. Energy levels fed had no significant effect on pullet weight, feed consumed, or mortality to 140 days of age.During the laying phase, hens that had been on the step-down protein feeding program reached 50% production 2.0 days earlier than birds subjected to the step-up protein feeding program. Hen-day production for the step-down and step-up pullet feeding systems based on 308 days’ records was 76.09 and 76.86%, respectively. Feed efficiency and mature body weight were not significantly affected by grower feeding programs. The largest egg size and highest laying house mortality were noted in hens grown on the step-down protein feeding program.

Dispersal of the Northern Fowl Mite, Ornithonyssus sylviarum (Canestrini and Fanzago), and the Chicken Body Louse, Menacanthus stramineus (Nitzsch), Among Thirty Strains of Egg-Type Hens in a Caged Laying House

From September 1978 through February 1979, dispersal of uncontrolled, naturally occurring populations of the northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), and the chicken body louse, Menacanthus stramineus (Nitzch) was studied on 30 strains of egg-type pullets reared to 20 weeks old on four growing rations before being housed for egg production. Hens representing all 30 strains and each of the four feeding regimens had mites. The northern fowl mite spread from initial infestations down the entire length of the house in 1 month; after four months, the chicken body louse had spread approximately two-thirds the length of a cage row in the house. Populations of the northern fowl mite increased from very light to extra heavy within 1 month and then began a slow decline.

The Influence of Environmental Temperature and Intermittent Watering on Resource Conservation in the Management of Brown Egg Type Hens in Wire Cages

Three hundred thirty-six brown egg type pullets, housed 3 birds per 30.5 × 45.7 cm cage in a modified stair-step system were subjected to two temperature and two drinking water treatments. The temperatures employed were 15.5 to 18 C and 21 to 24 C. Drinking water treatments utilized trough waterers in which a continuous flow of water was compared with 4 daily waterings of 15 min duration each. Treatment effects on feed consumption, hen-day egg production, egg weight, shell quality, albumen height, and body weight gain were measured. Data were collected for 48 weeks beginning with the onset of egg production at 22 weeks of age. Temperature treatments were maintained only for the first 24 weeks, the cool weather months, of the experiment.Ttreatments had no significant effect on egg production, egg weight, shell thickness, nor albumen quality. The warmer environment and 4 × 15 min water availability each resulted in a significantly lower feed consumption. Initially, body weight gains were greater in the cooler environment, but after 12 weeks production, gains were greater under 21 to 24 C treatment. At the end of the experiment no temperature treatment effects on body weight gain were in evidence. The intermittent drinking water treatment resulted in lighter body weights at 45 and 73 weeks of age.The warmer environment (21 to 24 C) combined with 4 daily waterings of 15 min duration each resulted in the greatest conservation of feed and drinking water.

Response of Thirty Egg-Type Stocks to Four Layer Diets Differing in Protein and Caloric Levels

Thirty strains of egg-type pullets hatched in March were fed four rations differing in protein and metabolizable energy. Diet 1 contained 15.1% protein and 2,770 kcal ME/kg of feed; diet 2, 15.1% protein and 3,010 kcal; diet 3, 17.2% protein and 2,770 kcal; and diet 4, 17.2% protein and 3,010 kcal ME/kg of feed. The 2,880 pullets were housed two birds per cage and fed the four diets ad libitum from 150 to 500 days of age. The objectives of the study were to evaluate the four dietary combinations and to search for the presence of genotype by diet interactions for egg production, egg weight, feed efficiency, body weight, and egg mass.Hen-day production for the four ration combinations was 73.40%, 74.38%, 75.61%, and 76.55% for rations 1, 2, 3, and 4, respectively. As protein and caloric level of the diets increased, average egg size, body size, and feed efficiency increased.Highly significant stock differences for egg production, egg size, feed efficiency, egg mass, and body weight were noted; however, diet by stock interactions for these traits were not statistically significant. There were highly significant stock-by-period and ration-by-period interactions for these traits. Despite the lack of statistical significance of the stock-by-ration interaction, there were stocks that deviated considerably from the average for egg production, body weight, and feed efficiency, particularly when fed the low protein-low energy ration, suggesting that some stocks should be fed specific laying diets.

Lysine and Methionine Needs of Growing Egg-Type Pullets

Two studies have been conducted with growing egg-production type pullets to examine the amino acid needs during the period of 6 to 22 weeks of age as it relates to hen-housed performance. Using a l...

Dietary Phosphorus Levels during Growth of Brown Egg Type Replacement Pullets

Caged Sex-Sal (DeKalb Warren) replacement pullets were fed diets containing .30%, .35%, or .41% available phosphorus from 0 to 20 weeks of age; in a second study pullets were fed the above levels plus a level of .25% available phosphorus from 2 to 20 weeks of age. Some of the pullets were fed diets restricted by 11 to 16% from 8 weeks of age. Reducing the dietary phosphorus did not harm weight gain, feed intake, feed conversion efficiency, bone ash or total calcium and inorganic phosphorus levels in plasma. There was a very small but significant reduction in weight gain and feed intake when .30% or .35% available phosphorus was fed from 0 to 4 weeks of age, but this difference disappeared at the later ages. With the nonstimulatory lighting schedule used, plasma phosphorus decreased markedly in the latter phase of the studies at all levels of dietary phosphorus and thus represented a nondietary age effect. These results show that dietary available phosphorus for caged, brown egg type pullets on full or restricted feeding programs can be decreased to a level as low as .25% from 2 to 20 weeks, and .30% from hatching to 20 weeks without adverse effect.

Effect of Feeding Plant By-Product Diets on Growth and Egg Production

Commercial strain-cross egg-type pullets were grown from 8 weeks of age to maturity on a diet containing 68% rice bran, 25% alfalfa, 5% dried molasses, and mineral, vitamin, and amino acid supplements. Similar diets in which wheat millfeeds or brewers dried grains replaced the rice bran produced satisfactory pullets but growth was slower and efficiency less than with rice bran diets.Laying diets containing up to 39.7% of rice bran supported egg production which was not significantly different from that produced with a standard corn-soy diet. A diet containing 74.7% of rice bran resulted in inferior production. A diet containing 74.7% of autoclaved rice bran resulted in egg production which was significantly better than that on the basal rice bran diet and not significantly different from that on the standard corn-soy diet.

Relationship of Initial Chick Weight to Body Weight of Egg-Type Pullets

In an attempt to determine whether initial chick weight affected body weight of commercial egg-type pullets just before the onset of egg production, two experiments were conducted. Results showed that initial chick weight (1 day of age) influenced average body weight of commercial egg-type pullets both at 12 and 18 weeks of age.

Response of three strains of egg-type pullets to three feed restriction regimes imposed during rearing

The productivity of heavy-, medium- and light-weight White Leghorn x Australorp pullets (216 of each strain) was established on three feed restriction regimes. The pullets were either restricted from 6 to 21 weeks of age to 80% of feed intake of pullets fed ad libitum, restricted in feeding time to 6 hours in every 48 from 6 to 21 weeks, or fed a diet containing 10% protein from day-old to 16 weeks of age. All restricted pullets ate between 19 and 37% less feed during rearing, were between 11 and 34% lighter at 21 weeks of age, and attained 50% production by 10 to 32 days later than pullets fed ad libitum. Strains differed in their responses to feed restriction as measured by mean body weight at 21 weeks, feed intake during lay, and feed per dozen eggs. Strain x rearing interactions were not observed for rate of lay, mean egg weight, total egg mass or rate of mortality. The biological responses were analyzed in economic terms using a computer simulation model. Restricting the feed intake of the heavy strain by any of these methods was more profitable, at ruling 1976 prices, than ad libitum feeding, because of the saving in feed cost and marked improvement in productivity. Performances were not improved by restriction in the light strain pullets, but feed cost was reduced by all three methods. With the medium strain, limiting the quantity of feed was more profitable than the other two methods.

Hepatic enzyme specific activities and fasting metabolic rate in pullets fed on controlled amounts of food during growth and lay

Variations in growth rate and daily egg output during lay were obtained by feeding controlled amounts of food to egg-type pullets from 6 to 70 weeks of age. Prior to sexual maturity the weight and lipid content of the liver were significantly increased when growth rate was severely restricted. These changes were associated with increases in the specific activities of hepatic lipogenic enzymes. Changes in hepatic enzyme specific activities in response to restricted feeding during growth were small compared with the increases observed at sexual maturity. During lay, restricted feeding had no significant effect on the liver lipid content or hepatic enzyme specific activities, but the specific activities of all the hepatic enzymes examined declined with age after sexual maturity. Restricted feeding had no influence on the fasting metabolic rate at any age. A reduction was observed between 13 and 20 weeks of age, but after a small increase at sexual maturity little further change was noted.

Effects of different feeding regimes during lay of egg-type pullets fed either high or low-protein diet during rearing

The performance of two groups of pullets reared on either high or low-protein diets was compared under six feeding regimes from 20 to 68 weeks of age. Pullets fed the low-protein (10 per cent) diet from 4 to 20 weeks ate about 20 per cent less food during rearing, were significantly lighter at 20 weeks and were delayed in attaining maturity compared with pullets reared on the high-protein diet. In the period from 20 to 36 weeks of age, pullets reared on the high protein diet laid at a higher rate when fed a laying diet containing 17 per cent protein than with a diet containing 15 per cent protein supplemented with methionine, or 13 per cent protein supplemented with methionine and lysine to the N.R.C. (1971) levels. In contrast, pullets reared on the low-protein diet laid fewer eggs on the 17 per cent protein diet than on the other two diets during the same period. However, no significant rearing x laying interaction was observed in average rate of lay during the whole laying year. The low-protein group laid fewer eggs from 20 to 68 weeks than the other group of birds, but the difference in production was not significant when calculated from maturity. Average rate of lay was not affected by the level of protein in the laying diet, but egg size tended to increase with increasing the level of protein. Increasing the level of protein gradually with the advance in lay had no effect on performance relative to birds fed the 15 or 17 per cent protein diet throughout lay. Restricting the feed intake during lay to 94 per cent of that consumed by full-fed controls, or restricting the time of feeding to four hours daily, reduced egg production by 7 and 6 per cent respectively, regardless of the rearing treatment. Rate of mortality throughout the experiment was not affected by any of the rearing or laying treatments. The results of this experiment indicate that the requirement during lay of pullets reared on a low-protein diet is between 51 and 53 g protein and 900 and 1000 mg of methionine per 4.1 9 MJ (1000 Kcal) ME. This protein concentration should be increased to between 58 and 60 g protein per 4.19 MJ ME if the pullets were reared on conventional diets. Restricting feeding during lay by either of the methods used in this experiment is detrimental to egg production.